Rep. Candice Miller is picky about bridges.

The Michigan Republican fought vigorously for federal funds for bridges in Port Huron, Mich., including attending a bridge opening in January 2010 and praising Transportation Secretary Ray LaHood in February 2010 for sending $30 million to her state to replace a bridge built in the 1960s.

But for another proposed bridge, she has raised concerns.

That proposal, a second bridge connecting Detroit and Windsor, Ontario, that is a priority for Republican Gov. Rick Snyder, “would hurt our established and existing crossings,” Miller wrote in an April 2008 letter.

The proposed bridge, the New International Trade Crossing, is, unlike the bridges Miller has supported, outside her district.

But it would also compete with the Ambassador Bridge — one of two privately owned international bridges in America — whose owner, the colorful billionaire Manuel “Matty” Moroun, has donated to Miller’s campaign.

According to a report from Citizens for Responsibility and Ethics in Washington, Miller has received $24,000 in campaign donations from a network of donors connected to Moroun.

In his campaign against the rival bridge, Moroun has donated hundreds of thousands of dollars to federal candidates, aired television commercials, spent a night in jail after misusing funds from a state construction project and even gained the support of tea party groups.

Supporters of the NITC have marveled at the durability of the opposition, which to them appears entirely the work of a self-interested owner who stands to lose toll money and is standing in the way of progress.

The CREW report highlights how the Moroun network’s donations have spiked at key moments in the debate and risen from $56,000 in the 2004 election cycle, in which the NITC was first proposed, to $639,000 in the 2010 cycle.

“It shows that lawmakers can be made to be much more sympathetic on an issue when they’re receiving campaign donations,” said Melanie Sloan, CREW’s president. It’s “impossible” to understand the opposition without the donations playing a key role, she added.

Moroun purchased the Ambassador Bridge, which was completed in 1929, in the 1970s for about $30 million. The bridge handles about 30 percent of trade between the U.S. and Canada and brought in $60 million in tolls in 2009.

It is “outdated and overwhelmed with traffic, leading to congestion and travel delays,” the CREW report claims.

In 2004, the Michigan Department of Transportation hired Moroun’s company to improve the roads leading to the Ambassador Bridge. The project, which was supposed to be finished by 2008, led to disagreements between state officials and Moroun.

The state ultimately sued Moroun, and an appeals court sent him to jail briefly in January.

Snyder has made the construction of another bridge across the Detroit River a priority. But many members of the Michigan Congressional delegation object.

In a May 2008 letter, Reps. Tim Walberg (R) and Thaddeus McCotter (R) and then-Reps. Carolyn Cheeks Kilpatrick (D) and Joe Knollenberg (R) also registered their opposition, raising concerns about costs and the displacement of people living in neighborhoods where the new bridge would connect to Detroit.

Less than two months later, Moroun and his associates donated thousands to both Walberg and McCotter. In July 2008, the Moroun network donated $14,000 to Walberg. In June 2008, Moroun and associates donated almost $5,000 to McCotter.

Walberg is the single largest recipient of donations from Moroun’s network in the 2012 cycle, receiving almost $83,000, according to the CREW report.

CREW calculated donations from Moroun’s network as donations from Moroun, his family and several executives from companies he owns.

In a statement, Miller said her concerns stem from her advocacy for a bridge in her district that she feels has been overshadowed by the interest in the proposed NITC. “My advocacy has always been for the Blue Water Bridge, which is located in my district and is the second busiest international crossing on the northern border. … The Blue Water Bridge has been the stepchild during this bridge controversy. These are concerns I have stated publicly, loudly, and often.”

McCotter’s and Walberg’s offices did not return requests for comment.

An interesting twist in the story is the involvement of Michigan tea party groups, including the local chapter of Americans for Prosperity and a Hillsdale College professor who operates a political consultancy firm.

The Michigan AFP chapter set up a website, detroitbridgeinfo.com, with a slogan: “There’s no such thing as a free bridge.” The site claims taxpayers will be on the hook for the cost of the bridge and that it isn’t needed since traffic is likely to decrease in light of Detroit’s difficult economic situation.

However, the Canadian government has offered to cover Michigan’s construction costs and recoup the money through toll revenue.

Gary Wolfram, an economics professor at Hillsdale College, a Michigan school known for its politically conservative faculty, conducted a study that Michigan AFP and others cited as reason not to build the second bridge.

The study was released by Hillsdale Policy Group, a consultancy group operated by Wolfram. It argued that traffic projections used to support the new bridge were inaccurate.

Moroun has also ramped up a lobbying and public relations campaign, including hiring Dick Morris, the Fox News commentator and former aide to President Bill Clinton, as a spokesman for his campaign against the bridge.

“The saga of the proposed bridge … shows how a single determined billionaire can wield disproportionate influence over the public agenda,” the CREW report says.